Problem: Solve for $x$ : $4\sqrt{x} + 4 = 9\sqrt{x} + 8$
Answer: Subtract $4\sqrt{x}$ from both sides: $(4\sqrt{x} + 4) - 4\sqrt{x} = (9\sqrt{x} + 8) - 4\sqrt{x}$ $4 = 5\sqrt{x} + 8$ Subtract $8$ from both sides: $4 - 8 = (5\sqrt{x} + 8) - 8$ $-4 = 5\sqrt{x}$ Divide both sides by $5$ $\frac{-4}{5} = \frac{5\sqrt{x}}{5}$ Simplify. $-\dfrac{4}{5} = \sqrt{x}$ The principal root of a number cannot be negative. So, there is no solution.